With Amos and Hosea, in the middle of the eight century before Christ, began that notable succession of religious thinkers whose utterances have been given permanent form in the prophetic books of the Old Testament. As we know from their writings, they are men of remarkable breadth, insight and power. While their greatest service to the world of their day, or of ours, was in the sphere of constructive religious thought, they were interested in the practical problems of human life, and touched it at many points. Their conviction that righteousness and sincerity were the fundamental elements of true life made them unsparing critics of social wrongs, idolatry, formalism, and worldliness, preachers of faith in God and love to man, and statesmanlike advisers on questions of public policy. Their chief distinction was their modest boldness. They spoke in the name of God, and claimed to give expression to his will. They looked at life from the standpoint of the Divine, approving or denouncing its varied phases according to their harmony with the ideal revealed to them. These men were called by their contemporaries 'prophets' or occasionally 'seers'. Another favourite term was 'men of God'. 'Prophet', the most frequently recurring term, literally meant 'the speaker' (Exod. 7:1), and suggested that the one to whom it was applied was commissioned to proclaim the will of God. This book presents the essence of the messages of a select group of these important prophets.